Springtime is a great time for bicycle adventures, says veteran bike tourist Tim Shea, with the wildflowers in bloom, seasonal rain showers mostly behind us and the summer heat not yet at full strength. One of his favorite excursions begins with a Friday night ride to San Jose on Caltrain and a stay overnight in one of the hotels near the airport. Early Saturday morning, Shea heads to the top of Mount Hamilton via Mount Hamilton Road, a 4,000-foot climb, but over relatively painless grades rarely exceeding 6.5 percent.

The reward? Once you get to the top and start down the back side of the hill, "you feel like you're out in the wilderness," Shea says. "You can see for miles." Continue on to the San Antonio Valley and feast your eyes on a vast carpet of the tiny yellow flowers known as goldfields, and maybe purple-blue lupines as well.

Spend Saturday night in a hotel in Patterson, and head for the Dublin/Pleasanton BART Station for a relaxing trip home.

Caltrain can also take you to several other Peninsula and Silicon Valley locations, including the Crystal Springs Reservoir, for gorgeous days of cycling. Go to www.bikesiliconvalley.org for maps and route information, and www.caltrain.com for more details on traveling with your bike.

Many a fine day trip also starts on BART. For instance, head to the Walnut Creek or Pleasant Hill stations for a climb up Mount Diablo.

All aboard!

Several Amtrak routes offer bicycle racks; to be sure your bike will have a spot on the train, reserve a space for $5-$10 when you buy your ticket. You can also bring your bike aboard as boxed or unboxed baggage or travel with a folding bicycle as a carry-on.

With a week free, Shea took the Capitol Corridor train to Sacramento, struck out for Redding on an Amtrak bus and spent several leisurely days cycling back to San Francisco. Amtrak's California Thruway Motorcoaches depart from a number of stations and allow you and your bike to travel the length and breadth of California, and even to Reno and Las Vegas, and as far north as Medford, Ore. Go to www.amtrak.com for more details, including a printable one-page map of train and bus routes.

Shea suggests taking an Amtrak bus from Martinez to Ukiah and riding "a very nice road" to Fort Bragg, or you can stay on the bus until you reach Arcata and ramble among the redwoods.

For an easy hop onto Amtrak's Capitol Corridor route, take BART to Richmond, which is also an Amtrak station. Depart the train in Suisun, Davis or Sacramento for an afternoon of exploring.

With Amtrak's combined train and bus service, you can visit Wine Country, Yosemite, Monterey, Santa Cruz, Barstow for some desert sun or Palm Springs for a round of golf.

Maps and more maps

This month, Google began offering maps and turn-by-turn directions for bicycling, an oft-requested and long-awaited improvement (maps.google.com). While the service is getting off the ground, it is probably a good idea to double-check directions against a bike map (San Francisco Bike Maps are available online at links.sfgate.com/ZJJW), or to ask your local cycling organization if in doubt.

Krebs maps are "very useful in planning rides," says Shea, who also often consults AAA maps to learn about back roads that may afford congenial cycling.

Bike About Town is presented by the San Francisco Bicycle Coalition, an 11,000-member nonprofit dedicated to creating safer streets and more livable communities by promoting the bicycle for everyday transportation. For more biking resources, go to www.sfbike.org.

-- The SFBC is leading a literary tour of S.F. 11 a.m.-2 p.m. Sun. Free-$5. Meet at the entrance to Alamo Square Park, Hayes and Steiner streets, S.F.

-- Michael Cramer discusses his travels on the bicycle path that divided East and West Europe for nearly 50 years at "Riding the Iron Curtain Trail." 6:30 p.m. Fri. SFBC offices, 995 Market St., suite 1550.